Electric power tool

ABSTRACT

An electric power tool has a plurality of separable housing parts including at least two shell elements oriented toward one another of a housing and one cup element of a housing, and the housing parts include one housing part of the cup element which at least partly embraces one housing part of the shell element from outside.

CROSS-REFERENCE TO A RELATED APPLICATION

The invention described and claimed hereinbelow is also described in German Patent Application DE 102005037255.4 filed on Aug. 8, 2005. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The present invention generally relates to electric power tools.

In the prior art, electric power tools that are embodied either as shell-type tools or as cup-type tools are known. Shell-type tools include a shell element of the housing, which in shell-type fashion surrounds corresponding functional units. In a cup-type tool, the functional units of the electric power tool are located in a cup element of the housing. Electric power tools with a plurality of separable housing parts are also known, in which at least one shell element of the housing and one cup element of the housing that are separate from one another are embodied.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an electric power tool which is a further improvement of the existing electric power tools.

In keeping with these objects and with others which will become apparent hereinafter, in the electric power tool of the invention, one housing part of the cup element at least partly embraces one housing part of the shell element from the outside. For instance, two shell elements oriented toward one another surround the interior of the electric power tool in the corresponding housing part. The shell elements have a parting seam in the axial direction.

A cup element, conversely, has a separation perpendicular to the axial direction. Preferably, according to the invention, the cup element is embodied with a larger circumference than the shell element, and as a result lubrication of the gear can be improved. This is due to the fact that the circumferential region in which the cup element embraces the shell element is embodied with double walls. A grease chamber located in the shell part is thus limited only to less space than in electric power tools in which the grease chamber is located as far as the one-walled housing part.

The lubricant or grease thus favorably remains in the vicinity of the components to be supplied, for instance a gear, and as a result the lubrication can be improved, and in particular the gear can be prevented from running dry quickly. This advantageously also lengthens the service life of the components, such as gear wheels, without putting limits on the design.

Preferably, the region of the shell element embraced by the cup element, as an extension of the shell element, plunges into the cup element, and the shell element and the cup element are axially in line with one another. The extension is favorably no longer visible from outside. Thus the extension of the shell element advantageously now has to meet only the technical requirements, without having to take intended design features into account. In the interior, conversely, an optimal amount of installation space is achieved. In the visible part, conversely, or in other words in the cup element that can be seen from outside, the electric power tool can meet ergonomic demands and still have a designer shape.

A gear is preferably located in the shell element, and the extension defines a grease area, located in the gear, of the shell element. In particular, the extension can closely surround gear wheels of the gear. In an especially preferred embodiment, a closure for the grease area located in the extension can be located in the cup element, and the grease area is operatively connected to the extension. The operative connection is due to the fact that the grease stays in the immediate vicinity of the gear wheels, which has the favorable effects on the lubrication mentioned at the beginning of this section.

In an advantageous refinement, the shell element and the cup element can be capable of being coupled together without tools, for instance by a connection on the order of a bayonet mount, a plug-type connection, or a lock, in which the housing parts of both the shell element and the cup element are secured against rotating relative to one another.

The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a, b, c show a view of a shell part of one embodiment of an electric power tool in accordance with the present invention in a side view (FIG. 1 a), a front view (FIG. 1 c), and a perspective view laterally from above (FIG. 1 b); and

FIGS. 2 a, b show a view of a cup part of the electric power tool in accordance with the present invention in the embodiment of FIG. 1, in a side view (FIG. 2 a) and a front view (FIG. 2 b).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 a, b, c, a shell element 10 of an electric power tool according to the invention is shown in various perspectives; located in the housing part 20 a of the electric power tool are a drive unit 16, not visible in FIG. 1, such as an electric motor, and a gear 13. FIGS. 2 a, b each show a cup element 11 in various perspectives, whose housing part 20 b includes mounts and bearings for a drive shaft, not shown.

The shell element 10 and the cup element 11 are axially in line with one another in the assembled state and can be coupled to one another by force- and/or form-locking; the assembly is preferably done without tools, for instance via a bayonet-mount-like closure, or requires only a simple assembly tool. In the assembled state, which is not shown in the drawings, the housing parts 20 a, 20 b have a substantially cylindrical cross section.

According to the invention, a housing part 20 a of the cup element 11 at least partly embraces a housing part 20 b of the shell element 10 from the outside. The region of the shell element 10 embraced by the cup element 11 plunges, as an extension 12 of the shell element 10, into the cup element 11. The extension 12 is outlined with a dashed line in FIG. 1 a and is a part of the shell element 10.

The extension 12 in particular is embodied with a smaller circumference than the housing part 20 b of the cup element 11 that embraces the extension 12.

A protrusion 17 on the upper circumference of the housing part 20 a of the shell element 10 is located such that when the cup element 11 is slipped on, it fits over the cup element 11 in the region 18. As a result, a secure connection is made between the shell element 10 and the cup element 11.

Because the extension 12, in the assembled state, is not visible from outside, it need not meet any designer requirements, either. Instead, the embodiment of the extension 12 can be adapted to the technical requirements. The extension 12 in particular defines a grease area 14 of the shell element 10, which region is located in the gear 13. The extension 12 surrounds gear wheels 15 of the gear 13 as closely as possible.

The cup element 11 thus forms a closure for the grease area 14 located in the extension 12. The grease area 14 is thus smaller than in the known electric power tools. Because of this dimensioning of the grease area 14, the grease remains in the vicinity of the gear wheels 15, thus preventing the gear 13 from running dry quickly.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in an electric power tool, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 

1. An electric power tool, comprising a plurality of separable housing parts including at least two shell elements oriented toward one another of a housing and one cup element of the housing, said housing parts including one housing part of said cup element which at least partly embraces one housing part of said shell element from outside.
 2. An electric power tool as defined in claim 1, wherein a region of said shell element which is embraced by said cup element plunges, as an extension of said shell element, into said cup element.
 3. An electric power tool as defined in claim 2; and further comprising a gear that is located in said shell element.
 4. An electric power tool as defined in claim 3, wherein said extension defines a grease area of said shell element, said grease area being located in said gear.
 5. An electric power tool as defined in claim 3, wherein said gear has gear wheels, said extension closely surrounding said gear wheels.
 6. An electric power tool as defined in claim 4, wherein said cup element is configured so that it forms a closure for said grease area located in said extension.
 7. An electric power tool as defined in claim 4, wherein said grease area is located such that it is operatably connected to said extension.
 8. An electric power tool as defined in claim 1, wherein said shell element and said cup element are configured so that they are coupleable to one another without tools. 